The subject of the invention is that of a functioning mechanism for a small caliber automatic weapon. The mechanism comprises a sear that moves from its starting position to its firing control position under the action of a rotating trigger, and a hammer having a rotating movement alternating between a cocked position and a striking position during the firing of a burst of rounds. The sear comprises a hooking element designed to come into contact with a bearing surface of the hammer in order to render the hammer immobile when the sear is in its starting position before firing the first round of the burst and when the sear has returned to its starting position after firing the last round of the burst.
One of the problems associated with this type of mechanism is the risk of silvering of the sear hooking element and/or of the hammer bearing surface, which cooperate with one another to ensure the immobility of the hammer. In fact, as the sear and the hammer are both moving at the same time, one must catch up with the other, such that the hooking element and the bearing surface often move over one another before coming into contact with one another. In other words, the hammer is not brought to a dead stop by the sear.
The silvering of the sear hooking element and/or the hammer bearing surface causes wear such that the safety of the weapon is likely to be endangered. One solution to this problem may consist in subjecting these parts to heat treatment, but that would increase their manufacturing cost.